Lithium base grease containing lead oleate, sulfurized lard oil and molybdenum disulfide



United States Patent LITHIUM BASE GREASE CONTAINING LEAD OLEATE, SULFURIZED LARD OIL AND M0- LYBDENUM DISULFIDE Lewis D. Loring, Bolton, and Henry J. Voss, Homewood, I]l., assignors to Sinclair Refining Company, New York, N.Y., a corporation of Maine No Drawing. Filed June 24, 1960, Scr. No. 38,456

3 Claims. (Cl. 252-18) The present invention relates to a grease composition of unusually high extreme pressure properties.

The increases in gear and bearing loading within re cent years and the more vigorous service conditions in other instances of metal to metal contact have made extreme pressure lubricants and lubrication a limiting factor in performance. Much difiiculty has been experienced in formulating greases capable of operating under severe conditions to protect efiectively metal surfaces which come in contact with the lubricant. It is well known that the high pressure occurring in certain types of gears and bearings may cause a film of lubricant to rupture with subsequent damage to the machinery. It has been shown that lubricants can be improved with regard to their protective effect on rubbing surfaces by the addition of certain substances so that excessive wear, scuifing and seizure which normally follow a break in the film of lubricant can be prevented. Ingredients of this character are called extreme pressure (E.P.) ingredients. Numerous materials are known to impart extreme pressure properties to lubricants, as for instance, compounds containing sulfur, chlorine, phosphorous or lead. However, the simple presence of these elements does not guarantee extreme pressure properties and various compounds that do have these properties can vary considerably in their effectiveness.

We have now found that greases having incorporated therein small effective amounts of lead oleate, sulfurized lard oil, and molybdenum disulfide exhibit surprisingly high extreme pressure characteristics. The lead soap of the present invention is lead oleate. The amount of sulfur in the sulfurized lard oil will usually range from about to 15%, preferably about 9 to 12% by weight.

The amount of the additives of this invention added to the grease is that sufiicient to impart extreme pressure properties to the grease. Thus, the amount of the additives will vary depending on the particular characteristics of the grease utilized. In general about 2 to 4 weight percent of lead oleate will be employed. The amount of sulfun'zed lard oil utilized is usually about 3 to 6 weight percent, preferably about 4 to 5 weight percent. The molybdenum disulfide component of the present invention is generally employed in effective amounts of about 0.5 to 3 weight percent, preferably about 1 to 2 weight percent.

The grease employed with the novel additive combination of this invention can be a mineral lubricating oil base stock thickened to grease consistency with a lithium soap, for instance, a lithoum soap of the ordinary saturated and unsaturated soap-forming fatty acids of about 12 to 20 carbon atoms including the hydrogenated fatty acids. Highly preferred soaps are the soap-forming h droxy fatty acids, e.g. 12-hydroxy stearic acid, and their simple esters and glycerides, such as hydrogenated castor oil. The amount of soap employed is that sufiicient to thicken the base oil to grease consistency. This amount is generally about to 50 weight percent. The base oils thickened to grease consistency are of lubricating vis cosity and can be petroleum lubricating oils derived from paraflinic, naphthenic, asphaltic or mixed based crudes. The oils may also be synthetic such as synthetic ester oils, e.g. di-Z-ethylhexyl sebacate. The composi- 3,015,023 Patented Jan. 2, 1962 tion of the present invention can also contain other additives such as antioxidants, corrosion inhibitors, and antiwear agents.

Lithium 12-hydroxy stearate-thickened greases prepared by in-situ soap formation and dehydration at a maximum temperature of about 300 to 350 F., e.g. 330 F., and containing the novel additive combination of the present invention were subjected to the Shell 4-ball wear test, the 4-ball extreme pressure test and the Timken test. These tests have been fully described in literature under the subject of anti-wear and extreme pressure testing. Thus, we will not go into detail concerning the procedure of each. The possible exception to the above is the Timken test. Details of this test can be found in US. Patent No. 2,715,612. The results of these tests are found in Table I.

Table I Grease Composition 1 2 3 4 Base Grease Ingredients:

Hydrogenated Castor Oil 14.10 13.14 13.07 12.50

Lithium Hydroxide 2.17 2.02 2.01 1.86

500 SUS at 100 F. Neutral on.-. 83.73 78.04 77.62 77. 34 Additives:

Lead Oleate 2. 30 2.30 2. 30

Sulfurized Lard Oil (12% S) 4.00 4. 00 4. 00

Unworked Pene 277 286 298 278 Worked Pene 270 293 203 289 Dropping Point, F 384 365 364 367 4-Ball Wear Test, 640 r.p.m.

C.-15 kg.2 Hr.

Avg. Wear, mm 0. 31 0. 39 0.43 0. 49 4-Ball EP test- MHL 20.0 45.0 55.3 67.4 Weld, kg 141 224 251 251 Timken Test Pass, lbs 3 45 60 70 Fail, lbs 0 50 05 75 As demonstrated by the T imken pass load, the extreme pressure properties of the grease containing the three component additive combination of the present invention are superior greases.

Five samples of greases containing a total of 8.3% of additives (the total amount of additives used with 2% M03 shown in Table I) were also tested. The results are shown in Table II.

Table II Grease Composition 1 2 3 4 Base Grease Ingredients:

Hydrogenated Castor Oil 12.92 12.92 12.50 12.50

Lithium Hydroxide 1.99 1. 99 1. 86 1. 86

500 SUS at 100 F. Neutral 76. 70 70.70 77. 34 77. 34

Additives:

Sullurized Lard Oil (12% S) Lead Oleate Sulfurized Sperm O Lead Naphthenate. 1 1032 Unworked Pene 260 286 290 261 292 293 3 4 We claim: amount of sulfurized lard oil is about 4 to 5 weight 1. A grease composition of improved extreme prespercent. sure characteristics consisting essentially of a petroleum base lubricating oil thickened to grease consistency with References Cited in the file of thls Patent lithium 12-hydroxy stearate soap, about 2 to 4 weight 5 UNITED STATES AT percent lead oleate, about 3 to 6 weight percent sulfurized lard oil and about 0.5 to 3 weight percent molyb- 2,156,803 Cooper et y 2, 1939 denum disulfide 2,449,510 Robertson Sept. 14, 1948 2 The grease composition of claim 1 wherein the 2,609,343 White at SePt- 1952 amount of molybdenum clisulfide is about 1 to 2 weight 10 2,858,273 Worth 281 1958 2,898,297 Schott Aug. 4, 1959 percent.

3. The grease composition of claim 2 wherein the UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. $015,623 January 2 1962 Lewis D. Loring et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below. I

Column 4, line-8, for "2,609,343" read 2 609 342 Signed and sealed this 24th day of July 19.62.

(SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Attesting Officer Commissioner of Patents 

1. A GREASE COMPOSITION OF IMPROVED EXTREME PRESSURE CHARACTERISTICS CONSISTING ESSENTIALLY OF A PETROLEUM BASE LUBRICATING OIL THICKENED TO GREASE CONSISTENCY WITH LITHIUM 12-HYDROXY STEARATE SOAP, ABOUT 2 TO 4 WEIGHT PERCENT LEAD OLEATE, ABOUT 3 TO 6 WEIGHT PERCENT SULFURIZED LARD OIL AND ABOUT 0.5 TO 3 WEIGHT PERCENT MOLYBDENUM DISULFIDE. 